1. Field of the Invention
This invention relates generally to pedal powered recumbent tricycles and particularly to chain driven multiple speed planetary transmissions for pedal powered vehicles.
2. Description of the Prior Art
The most common multiple speed bicycles and tricycles use a chain and derailleur system with the chain exposed. The chain requires periodic cleaning and oiling to preserve pedalling efficiency and to prevent premature chain failure, and chain maintenance becomes particularly troublesome in dusty areas. Also when the rider is bearing down hard on the pedals on a hill, the derailleur frequently will not carry the chain to a lower gear so that the cyclist must anticipate the terrain and shift gears before getting on a hill in a gear that is too high. Further, all the gears with a conventional chain derailleur system are not efficiently usable because of the excessive angle the chain makes with the sprockets with some sprocket combinations. These problems are eliminated with the enclosed drive of the present invention, as will be seen.
It is well known that the aerodynamic drag coefficient for bicycles and tricycles with full fairings is a small fraction of that for unfaired bicycles with the rider in the conventional crouched riding position. A rider expending about one quarter horsepower on a conventional racing bicycle on level ground travels at twenty miles an hour, while with the same effort a fully faired recumbent tricycle will travel about thirty miles an hour. A fairing can also provide protection in cold or wet weather.
It is likely that the optimum pedal powered vehicle for everyday transportation as well as extended trips will ultimately be virtually maintenance free, extremely efficient, suitable for low cost mass production, and suitable for operation in areas as rainy as Seattle or as hilly as San Francisco either with or without a full fairing. The present invention is an attempt to satisfy these objectives.